KR100315520B1 - A micro-fan - Google Patents

Abstract

The present invention relates to a micro fan having a cross-sectional shape of an air foil and helical torsion, thereby generating an optimum amount of wind and pressure, thereby increasing rotational efficiency and reducing power consumption and rotational noise. The helical twist is applied to the span between the hub end and the duct tip of the blade to prevent surging and noise To reduce and improve performance.

Description

A micro-fan

The present invention has an airfoil shape and twists between the hub side blade end and the tip end of the duct side blade at a predetermined angle, thereby applying helical twisting, so that the optimum air flow rate and wind pressure are generated during the rotation of the blade, thereby improving rotation efficiency. The present invention relates to a micro-fan that enables the rise, power consumption, and rotational noise to be reduced.

The micro fan is mainly used for cooling the driving heat of a drive device that generates heat during driving such as a microprocessor or a VGA card in a limited space such as a laptop or a personal computer. It is common to use a single rotation axial flow fan.

This micro fan is currently applied as a case of directly attaching to a microprocessor and attaching to an internal structure alone in a notebook, etc. In particular, the personal computer itself is gradually smaller in size, whereas the CPU of each driving device has a large capacity and a high speed. Therefore, the load capacity is rapidly increased and generates very high heat on its own.

The driving heat in the CPU can lead to an inoperable state caused by overheating, which can lead to serious device failures that cause damage to major components.

Therefore, while CPU cooling, which was not considered so serious in the past, has emerged as a very important task that cannot be overlooked in recent years, the current CPU cooling fan is reaching a technical limit that cannot be sufficiently coped with.

On the other hand, the cooling by the micro fan can be considered as a method of increasing the air volume of the fan first, and the air volume of the fan is determined by various variables such as blade size, shape, and operating rotation speed. Problems of power consumption, power consumption and noise generation must also be considered.

Therefore, in designing the fan, high performance such as preventing energy loss due to separation of the flowing air, reducing noise, maximizing the static pressure rise while minimizing the loss between the inlet and the outlet of the wing, etc. It is necessary to satisfy the conditions that can be exerted.

In particular, most fan noises have been found to be variable in terms of rotational speed, wing tip clearance, number of wings, chord length, camber, and wing sweep. have.

FIG. 1 is a plan view showing the structure of a micro fan which is generally used. Reference numeral 1 denotes a hub fixed to a motor shaft and rotated. Reference numeral 2 denotes a blade integrally formed on an outer circumferential surface of the hub 1. Silver is a duct that surrounds the hub 1 and the blade 2 from the outside while inducing air from the outside through a space that is finely spaced from the blade 2.

The hub 1 is a rotating member of the fan motor, and a magnet is attached to the inside thereof, and the rotating member of the motor rotates by electromagnetic force by interaction with a stator coil, which is a fixed member, when a magnet is attached thereto.

The blade 2 is radially provided on the outer circumferential surface of the hub 1 integrally and rotates together with the hub 1 to supply cold air from the outside to supply the microprocessor.

And the duct (3) is provided on the outside of the blade (2) serves to guide the air drawn by the blade (2) to the microprocessor while substantially surrounding the outside of the blade (2).

2 shows an enlarged front view of the blade 2 provided in the hub 1 in the conventional micro fan, wherein the blade 2 in the conventional micro fan has an arc shape in which the cross section is curved upward. In most cases, one side is coupled to the hub 1 and is inclined downward to the other side.

Meanwhile, the duct 3 having a shape surrounding the outside of the blade 2 while being spaced apart from the outer circumferential surface of the blade 2 at minute intervals is separated from the microprocessor such as a screw while the bottom is integrally connected with the fixing member of the motor. It is fastened using the fixing means.

In particular, the guide hole (3a) formed by finely spaced between the outer circumferential surface of the blade (2) and the inner circumferential surface of the duct (3) serves as a guide to smoothly guide cold air introduced by the blade (2) to the microprocessor. Done.

Therefore, when power is supplied to the motor and the hub 1 starts to rotate, a plurality of blades 2 integrally provided in the hub 1 rotate and air is sucked from the outside by the pressure difference between the surfaces of the blades 2. Supplied to the microprocessor.

This inflow of air has a low pressure because the upward curvature of the blade 2 lowers the internal pressure rather than the outside relative to the surface of the blade 2 when the blade 2 rotates together with the hub 1. This is done by the principle of moving to.

However, the shape design of the blade 2 is very simple because most of the micro-fans currently used are manufactured only for the purpose of sucking air from the outside. That is, the air volume of the general fan is determined by the size and shape of the blades and the number of rotations of the blades. However, the cross-sectional shape of the blade 2 currently applied to the micro fan has a predetermined value at both ends of the straight bottom surface as shown in FIG. It consists of a very simple shape connected in the shape of a circular arc, which is a radius, and the angle of the blade 2 inclined with respect to the hub is the same as that of the hub side end and the duct side tip end, and the bottom side to the length of the bottom side. The camber ratio, the ratio of the height difference between the center and the thickness centerline, is about 10%, which is relatively large, and the cord line lengths at the hub end and the duct tip are also formed equally.

When the blade 2 having such a shape is integrally coupled with the hub and driven, the change in the wind pressure according to the change in the amount of air generated by the micro fan according to various rotational speeds of the blade, that is, 8500 rpm, 9500 rpm, and 10500 rpm, will be described in the following table. It will show the same performance characteristics as 1.

Air flow rate (cmm) Wind pressure (mmAq) Air flow rate (cmm) Wind pressure (mmAq) 8500 rpm 9500 rpm 10500 rpm 8500 rpm 9500 rpm 10500 rpm 0 1.4306 1.6943 2.2725 0.017 0.3564 0.4684 0.655 0.001 1.3435 1.6129 2.1748 0.018 0.3357 0.4476 0.6426 0.002 1.2357 1.497 2.0445 0.019 0.3191 0.4228 0.6343 0.003 1.1444 1.385 1.9223 0.02 0.2734 0.4103 0.6135 0.004 1.0449 1.2813 1.8042 0.021 0.2361 0.3688 0.5845 0.005 0.9495 1.1818 1.6984 0.022 0.178 0.3315 0.5638 0.006 0.85 1.0822 1.5592 0.023 0.1241 0.2776 0.5264 0.007 0.7712 0.9785 1.4472 0.024 0.0661 0.2237 0.4974 0.008 0.6675 0.8831 1.3186 0.025 0 0.178 0.4476 0.009 0.5804 0.7919 1.2067 0.026 0.1075 0.3896 0.01 0.5057 0.7048 1.0864 0.027 0.0536 0.3232 0.011 0.4435 0.6094 0.991 0.028 0 0.2651 0.012 0.4145 0.5555 0.8707 0.029 0.1863 0.013 0.4103 0.5223 0.7919 0.03 0.1158 0.014 0.4062 0.5099 0.7421 0.031 0.0412 0.015 0.3979 0.4933 0.6882 0.032 0 0.016 0.3813 0.485 0.6758 0.033

On the other hand, Figure 3 is shown as a graph using a numerical value output as shown in Table 1.

It can be seen from the above characteristic changes according to the tables and drawings that the micro fan has a smaller wind volume and a larger wind pressure, and a larger wind volume decreases gradually.

In addition, it can be seen that the characteristic change of the wind pressure appears differently depending on the rotational speed of the blade.

On the other hand, when the wind pressure decreases with the increase of the air volume, as in this action, the wind pressure decreases rapidly, and the surging phenomenon is caused by the unstable air flow at the point where the air pressure becomes smooth, and thus the fan driving efficiency is reduced. There is a problem of being reduced.

This is caused by a stall that hinders performance during sudden changes in wind pressure. This means that as the hub ratio increases, the blowing performance is characterized by the highest pressure and the steepness of the operating area. It is due to the principle of deepening.

Therefore, the conventional microfan has a limitation that does not exhibit the required cooling efficiency, resulting in overheating of the device. To solve this problem, a larger load capacity is required to further increase the rotational force of the microfan. There is a disadvantage.

In addition, delamination of the flow air due to vortexing occurs at the tip, which is structurally the outer periphery of the blade, and this delamination disturbs the surrounding flow field, thereby providing a cause of overall performance degradation and noise increase.

On the other hand, recently developed high-capacity and high-speed microprocessors provide faster processing speeds, so proper cooling is impossible by conventional blades. Therefore, there is a need for a fan blade that can respond quickly.

The present invention has a main object of maximizing the wind pressure and the amount of air by adopting the cross section in the shape of an airfoil so as to be twisted at an angle from the hub side end to the duct side end.

Another object of the present invention is to increase the rotational efficiency of the fan so that the noise can be significantly reduced.

Another object of the present invention is to reduce the power consumption while reducing the rotational load.

1 is a plan view of a typical micro fan,

2 is an enlarged side view of a portion in FIG. 1, FIG.

3 is a graph showing the performance characteristics of the micro fan to which the blade of FIG.

4 is a perspective view of a micro fan according to the present invention;

5 is a front view of FIG. 4;

6 is a sectional view of a blade according to the present invention;

7 is a detailed structural diagram of a blade according to the present invention;

8 is a plan view of a blade according to the present invention;

9 is a graph showing the performance characteristics change by the microfan according to the present invention.

<Description of the symbols for the main parts of the drawings>

10 hub 20 blade

In order to achieve the above object, the present invention is a hub rotatably provided about an axis,

A plurality of blades formed radially on the outer peripheral surface of the hub,

The blade;

The cross section is an airfoil shape that generates a larger lift than the drag force, and one end rounded by a small radius of the cross section is called a leading edge, and the other end is called a trailing edge, and the leading edge and the trailing edge are connected. When the straight line is called the cord line, the thickness centerline between the leading edge and the trailing edge is called the min line, and the inclination angle of the cord line with respect to the horizontal line drawn from the leading edge is called the blade angle.

The angle of the end in contact with the hub side of the blade is about 24 ° to 34 °, the blade angle of the tip end of the duct side is about 18 ° to 28 °, and the blade angle difference between the tip angle of the tip end on the duct side from the hub side Torsion angle is characterized in that it is made of a configuration having a helical twist of 2 ° ~ 12 °.

Hereinafter, described in detail with reference to the accompanying drawings a preferred embodiment of the present invention.

In general, important variables to consider in order to achieve high performance in fan design include rotation speed, blade angle, number of blades, blade shape, and so on. In order to maximize the static pressure rise, the most important consideration is the shape of the blade.

The shape applied to the design of the blade is usually the British C (Circular Arc) and the American NACA (National Advisory Committee for Aeronautics), in order to prevent energy loss due to air separation. The angle will be determined.

The present invention applies the torsion angle to the blade of the airfoil while applying the airfoil shape of the NACA series that is currently most applied for the optimal blade shape by changing the elements such as camber and thickness of the airfoil The blade is to be implemented.

In particular, the present invention adopts the NACA 4 series mainly used in the low speed region among the NACA series, and applies the optimal thickness, demonstration length, and the like of the blade.

4 is a perspective view of a micro fan according to the present invention, and FIG. 5 is a side view of the micro fan of FIG. 4.

Accordingly, the present invention allows the plurality of blades 20 to be integrally formed radially on the outer circumferential surface of the hub 10 of the motor while the blades 20 are airfoils of the NACA4 series that the cross section is used in the design of the aircraft wing, blade surface Is characterized by being twisted at a predetermined angle.

FIG. 6 illustrates a cross-sectional structure of a blade in the micro-fan shown in FIG. 5, in which the cross-section of the blade is an airfoil shape in the present invention. Is generated.

In the drawing, one end rounded to a predetermined radius of the cross section of the blade is called a leading edge, and the other end corresponding thereto is called a trailing edge.

The straight line connecting the leading edge and the trailing edge is called a chord line, and the thickness centerline of the blade between the leading edge and the trailing edge is called a min line.

In this case, the min line is composed of two parabolas based on the position where the y-coordinate is the maximum value as follows, and the parabolic equation is defined as follows.

And for the thin line, the thickness distribution of the blade

On the other hand, the upper surface (O _U ) and the lower surface (O _L ) of the blade due to the thickness distribution can be obtained by the following equation.

The upper surface O _U , ,

Bottom surface (O _L ) , ,

At this time to be.

In the NACA4 series, the blade has a shape in which the leading edge, which is the end of one side, is rounded to a predetermined radius. The radius is a {r} _ {which is a straight line at the end of the code line with a slope at x / c = 0.005. t} = 1.1019 {t} ^ {2}.

Meanwhile in the above drawings,

c: code line length

m: maximum ordinate of the min line in the code component

p: position from code line in m

{r} _ {t}: leading edge radius corresponding to thickness ratio t

t: the maximum thickness of the cross section in the code component

x: Surface abscissa of code line

{x} _ {L}: the abscissa of the lower surface of the wing

{x} _ {U}: the abscissa of the upper surface of the wing

{x} _ {c}: the abscissa of the min line

{y} _ {L}: Longitudinal coordinate point of the lower surface of the wing

{y} _ {U}: Longitudinal coordinate point of the upper surface of the wing

{y} _ {c} is the ordinate of the Min line

{y} _ {t}: Surface coordinate point of the symmetry part

The blade of the airfoil as described above extends as a predetermined length from the hub 10 side end to the tip end of the duct side, and the span between the hub end and the tip end of the duct side at this time is

( )

It is the most prominent feature of the present invention to have a helical twist that satisfies.

At this time

= Freestream velocity,

R is the spanwise position,

D: Fan diameter (= 2 {R} _ {tip}, fan diameter)

Q: volumetric flow rate (㎥ / min)

{R} _ {tip}: Rotor tip radius (mm)

to be.

In other words, the present invention uses the airfoil of the NACA4 series that mainly applies the cross-sectional shape of the blade to the wing of the aircraft while twisting the span extending from the hub end to the duct tip end at a predetermined angle so that the blade area and maximum thickness and The angle of the blade is to be formed in the optimum conditions.

According to the drawings illustrating a preferred embodiment of the present invention in more detail as follows.

Figure 7 is an enlarged side view of a part of the micro-fan according to the present invention, 10 is a hub of the motor.

At this time, the cross section of the blade 20 is a blade shape, that is, the airfoil shape of the NACA4 series as described above.

That is, the min line, which is the thickness centerline of the blade 20 having an airfoil shape, has two parabolic equations, that is, the point where the height difference is the largest with respect to the code line.

In this case, the min line (T _M ) (H _M ) and the cord line (T _C ) (H _C ) are respectively formed in the duct side tip end and the hub side tip end as shown in the figure.

On the other hand, the thickness distribution of the blade 20 on the basis of the min line is constant from the hub side end to the duct side end, and this thickness distribution is defined by the following relationship.

By the short line and the thickness distribution, the upper and lower surfaces of the blade 20 can obtain the coordinate values by the following relationship.

,

,

In addition, the leading edge, which is one end of the blade 20, is rounded in a circle of {r} _ {t} = 1.1019 {t} ^ {2} which is a straight line radius at the end of the code line with a slope at x / c = 0.005. Be sure to

And the ratio of the maximum height difference between the code line and the min line to the length of the code line ( ) Has a camberby.

Meanwhile, the blade 20 having the airfoil cross section has a span extending from the hub side to the duct side by a predetermined length, and the span is a relational expression.

( )

Have a helical twist that satisfies

For this helical torsion, in this embodiment, as shown in Fig. 7, the forming angles of the hub 10 side end of the blade 20 and the tip end side of the duct side are formed differently.

This helical torsion is determined as the set angle of the hub 10 side end and the duct side tip end of the blade, the blade angle, that is, the inclination angle of the cord line with respect to the horizontal line drawn from the leading edge of each end. The blade angle, which is the inclination angle of the cord line H _C with respect to the horizontal line of the hub 10 from the leading edge of the blade 10, has an angle of about 24 ° to 34 °, and the blade angle of the tip end provided on the duct side is about Have an angle of 18 ° to 28 °.

And the ratio of the maximum height difference between the cord line and the pin line to the length of the cord line in each cross section of the blade having the blade angle described above. ), The camber ratio is most preferably 4 to 16%.

In addition, it is best that the blade angle difference between the hub 10 side end of the blade and the tip end of the duct side is 2 ° to 12 °.

The most preferable shape of the blade formed in such a configuration is the camber ratio of 8%, the angle of the blade 20 is 28.79 ° end of the hub 10 side, the tip end 22.57 °, the hub 10 side The torsion angle from tip to tip is 6.22 °.

As shown in FIG. 8, the length of the cord, which is the length between the leading edge and the trailing edge of the blade 20, is such that the length of the tip end side is formed to be larger than the hub 10 side end. Can be increased to the maximum.

In FIG. 8, R _D is a duct radius (mm), R _hub is a rotor hub radius (mm), and R _tip is a rotor tip radius (mm). As the gap between the tip end of the blade 20 and the duct is narrower, Although it is good, it is most preferable to keep it at about 0.5 mm because of difficulty in manufacturing.

The characteristics of the micro fan according to various rotational speed changes according to the present embodiment are shown in Table 2 below.

Air flow rate (cmm) Wind pressure (mmAq) Air flow rate (cmm) Wind pressure (mmAq) 8500 rpm 9500 rpm 10500 rpm 8500 rpm 9500 rpm 10500 rpm 0 1.8775 2.358 2.928 0.018 0.5057 0.7255 1.0407 0.001 1.7757 2.248 2.8058 0.019 0.4642 0.6799 0.9785 0.002 1.6699 2.1218 2.6756 0.02 0.4311 0.6426 0.9246 0.003 1.5675 1.9875 2.529 0.021 0.3854 0.6053 0.8707 0.004 1.4555 1.8857 2.4068 0.022 0.3357 0.5555 0.8209 0.005 1.356 1.7757 2.2725 0.023 0.2776 0.5099 0.7836 0.006 1.2564 1.6577 2.1544 0.024 0.2278 0.4599 0.738 0.007 1.1693 1.5053 2.0241 0.025 0.1656 0.3979 0.6882 0.008 1.0739 1.4182 1.9142 0.026 0.0992 0.3398 0.6343 0.009 0.991 1.3145 1.8002 0.027 0.0246 0.2776 0.5762 0.01 0.9288 1.2274 1.6943 0.028 0.2071 0.4601 0.011 0.8541 1.1444 1.6007 0.029 0.1241 0.3979 0.012 0.7877 1.0822 1.5177 0.030 0.495 0.3191 0.013 0.7172 1.0325 1.4265 0.031 0.0038 0.2444 0.014 0.6592 0.9288 1.356 0.032 0.1615 0.015 0.6053 0.8707 1.2647 0.033 0.0785 0.016 0.5638 0.8251 1.1859 0.034 0.008 0.017 0.5347 0.7794 1.1071 0.035

9 is a graph showing the characteristic change according to the above table, and it can be easily seen that the variation of the wind pressure becomes very gentle compared to the conventional micro fan through the change of the air volume.

On the other hand, the micro-fan according to the present invention may be formed by the following absolute coordinate values.

That is, a plurality of blades 20 are formed radially to the outer circumferential surface of the hub rotatably provided about an axis, and the blades have coordinates of the upper surface of the hub side.

X Y Z 0.000000 0.000000 8.700000 -0.138667 0.848028 8.658570 0.004639 1.625992 8.546704 0.264198 2.327542 8.382873 0.619004 2.944328 8.186631 1.029781 3.473029 7.976720 1.480217 3.941332 7.756023 1.96664 4.353728 7.532268 2.486875 4.715405 7.311290 3.039662 5.031621 7.097379 3.624660 5.307311 6.893652

And the duct top surface coordinate is

X Y Z 0.000000 0.000000 11.350000 -0.214333 1.023977 11.303720 -0.126138 1.997808 11.172790 0.099048 2.894330 10.974760 0.440899 3.699310 10.730220 0.856263 4.404663 10.460470 1.321298 5.036864 10.171160 1.832326 5.599416 9.872642 2.387100 6.097404 9.573096 2.984470 6.536602 9.278758 3.624168 6.922854 8.994254

And the hub side coordinates are

X Y Z 0.000000 0.000000 8.700000 0.396161 0.737933 8.668648 0.644208 1.437582 8.580405 0.909862 2.082332 8.447124 1.214126 2.670698 8.279938 1.559095 3.222821 8.081054 1.923898 3.728567 7.860521 2.312183 4.187325 7.626029 2.726197 4.600498 7.384133 3.167128 4.970913 7.140029 3.635339 5.302281 6.897522

And the duct side lower surface coordinate is

X Y Z 0.000000 0.000000 11.350000 0.329121 0.968701 11.308590 0.530347 1.872718 11.194440 0.769176 2.709496 11.021850 1.066046 3.477411 10.804170 1.415488 4.196884 10.545550 1.792875 4.856730 10.258400 2.201882 5.456312 9.952446 2.644758 5.997341 9.636100 3.122651 6.483214 9.316138 3.635830 6.918398 8.997682

Most preferably, it is formed to be.

When the blade 20 is formed along the coordinate value, the cross section is an airfoil shape and the blade angle from the hub 10 end to the tip end on the duct side has a helical torsion by a predetermined torsional angle. .

As described above, the present invention increases the flow rate and the static pressure as compared to the past, thereby reducing the influence of drag or friction caused by the tip vortex due to the reduction of the tip gap, thereby promoting more efficient air flow through the blade surface.

In addition, the helical torsion is applied to the blade to prevent the pressure decrease due to surging, and the effect of reducing the noise by reducing the resistance is expected.

Claims (6)

A hub rotatably provided about an axis, A plurality of blades formed radially on the outer peripheral surface of the hub, The blade; The cross section is an airfoil shape that generates a larger lift than the drag force, and one end rounded by a small radius of the cross section is called a leading edge, and the other end is called a trailing edge, and the leading edge and the trailing edge are connected. When the straight line is called the cord line, the thickness centerline between the leading edge and the trailing edge is called the min line, and the inclination angle of the cord line with respect to the horizontal line drawn from the leading edge is called the blade angle. The angle of the end portion in contact with the hub side of the blade is about 24 ° to 34 °, the blade angle of the tip end of the duct side is about 18 ° to 28 °, and is the angle difference between the blade side between the hub end and the tip end of the duct side. Torsion angle of the span is a micro fan with a helical torsion of 2 ° to 12 °. The method of claim 1, wherein the blade A microfan, wherein the tip end side cord length is formed longer than the cord length of the hub side end. A hub rotatably provided about an axis, A plurality of blades formed radially on the outer peripheral surface of the hub, The blade; The cross section is an airfoil shape that generates a larger lift than the drag force, and one end rounded by a small radius of the cross section is called a leading edge, and the other end is called a trailing edge, and the leading edge and the trailing edge are connected. When the straight line is called the cord line, the thickness centerline between the leading edge and the trailing edge is called the min line, and the inclination angle of the cord line with respect to the horizontal line drawn from the leading edge is called the blade angle. The ratio of the maximum height difference between the cord line and the min line to the length of the cord line in the cross section of the blade ( ), The camber ratio is 4 to 16%, the blade angle of the end facing the hub side is about 24 ° to 34 °, the blade angle of the tip end of the duct side is about 18 ° to 28 °, and the hub side which is the blade angle difference A torsion angle of the span between the tip ends of the duct side from the end is a micro fan having a helical twist of 2 ° to 12 °. The method of claim 2, wherein the blade A microfan, wherein the tip end side cord length is formed longer than the cord length of the hub side end. A hub rotatably provided about an axis, A plurality of blades formed radially on the outer peripheral surface of the hub, The blade; The cross section is an airfoil shape that generates a larger lift than the drag force, and one end rounded by a small radius of the cross section is called a leading edge, and the other end is called a trailing edge, and the leading edge and the trailing edge are connected. When the straight line is called the cord line, the thickness centerline between the leading edge and the trailing edge is called the min line, and the inclination angle of the cord line with respect to the horizontal line drawn from the leading edge is called the blade angle. The ratio of the maximum height difference between the code line and the push line to the length of the code line ( ), The camber ratio is 8%, the blade angle of the end facing the hub side is about 28.790 °, the blade angle of the tip end of the duct side is about 22.57 °, and the tip end of the duct side from the hub side end which is the blade angle difference Micro pan with helical torsion with span angle of 6.22 °. The method of claim 5, wherein the blade A microfan, wherein the tip end side cord length is formed longer than the cord length of the hub side end.